that was the glitch I had to fix... if you caught a dog, it would not disappear, and if you killed one BOTH event dogs would disappear (the roaming dog is not altered). but its fixed in 1.1, you will just have 2 extra sprites in a room because you swapped from 1.0 to 1.1... if you started from 1.1 those 2 extra sprites would be gone...

you are quite close to mew if you are in cerulean... just talk to everyone around the area and someone will head you in the right direction.